Heat saving unit



Sept. 14, 1954 J. CAMPBELL HEAT SAVING UNIT Filed Aug. 13, 1953 w 8 2 H 7 3 9 2 W 2 I!,\/ 3 Z a ll W hyveryfor -John Campbell a,

Patented Sept. 14, 1954 UNITED-STATES PATENT OFFICE HEAT SAVING UNIT John Campbell, Winnipeg, Manitoba, Canada Application August 13, 1953, Serial No. 374,052

3 Claims. '1

The invention relates to an attachment for the smoke pipe of a stove or furnace, for the purpose of transferring further heat energy from the hot gases passing therethrough to the atmosphere in the building.

The principal objects of the present invention are; to construct a unit which will replace a section of aheater or furnace smoke pipe; said unit directing the exhaust gases, passing therethrough, into a series of separate narrow passages for quick transfer of heat from these gases to the walls of the passages; provide free air circulationaround and between the exterior walls of said passages for dissipation of the heat therefrom to said air; and then direct said gases back toa singlepipe for final flow up a chimney.

A further object of the invention is to provide means for diffusing the flow of hot gases, normally passing intact through the central part of a smoke pipe, such that they will be distributed through the narrow passages for spread contact over the walls thereof for eflicient transfer of heat thereto.

Still further objects of the invention are; to construct the unit in a novel manner for economical manufacture; simplicity of assembly thereof; sturdy and strong in use; efficient in operation; cheaply repaired; and such that the construction will give many years of satisfactory service. a

The above important objects are attained by forming a series of flat-like pipes; the ends of these pipes being connected together by slidable strips to form a ring of spaced lengthwise flues; connecting these flues, at each end, to single entry and exit pipes; and closing the ends of the central area, between the flues, with director plates for smooth flow of the gases between the pipes and the flues. The details of the above construction will now be explained, reference being .had to the accompanying drawings in which:

Figure 1 i a side view of a stove with the invention connected in the smoke pipe thereof.

T Figure 2 is a central vertical section through the heat saving unit itself.

Figure 3 is a horizontal cross sectional view at 33,' Figure 2.

1 Figure 4 is a partial perspective view of the lower end of one of the passage flue pipes.

Figure 5 is a perspective view of one of the connecting strips.

Figure 6 is a perspective view of one of the director plates.

Figure 7 is a view showing a modified method of applying the invention to a furnace smoke pipe and for passage of the heated air therefrom.

In the drawings like characters of reference indicate corresponding parts in the several figures.

A series of flattened pipes or flues I form the central part of the unit and they are made from sheet material. The original blank (not shown), from which these flues were formed, was rectangular in shape with all four corners cut off at an angle, as indicated at 2 in Figure 4. In forming a flue from the original blank, a side 3 is bent over in a folding machine, as indicated at' l. The angled corners are also folded in the same manner, as at 5, and then a right-angled bend is formed a little farther in, as indicated at 6. Accordingly, an angular folded shelf 1 is produced at each corner and for the length of the cut-off. The two sides of the blank, some distance in from the edges, are lengthwise folded in a slight bend, as at 8, and then the central portion is rolled, as'at 9, to bring the two sides together with the edge of the opposite side In within the fold 4 of the side 3. Thus, a flat-shaped flue is formed with one edge rounded, the other edge pointed, and with each end of said pointed edge provided with outwardly projecting angular shelves. Each end of the flue is closed, between the parallel sides by cross plates H (see Figure 2) but the triangular-shaped end spaces [2 of the corners are left open.

A series of connecting strips l3 (see Figure 5) are formed from fiat material. These strips are of an elongated rectangular-shape. Each length wise edge is turned over by a folder and on the same side of the strip, as indicated at I4, to form hook-shaped edges therealong.

In forming'the central part of the heat saving unit, two of the flues I are placed side by side and connected together at each end by hooking the turned edges M of the strip I3 to each of the adjacent hook-shaped shelves of the sloping corners of the flues. The strips are slid therealong for thefull length of the shelves. Further flues are then connected or added in the same manner until a complete circle of same are formed, as shown in Figure 3, the strip spacing the flues apart. Before the last few lines are connected into the complete circle, a pair of cone-shaped director plates I5 (see Figure 6) are inserted in the central part of the assembly and one moved to each end in reverse relationship. That is; each have their pointed central part I! pointing away from the centre of the unit. Each of these director plates have their periphery V-slotted at intervals therearound, as at I8. These V-slots are received around the pointed edge of each of the flues I while the curved parts of the director plates rest on the inner ends of the connecting strips I3. The last flues are then connected as previously explained to complete the circle.

A pair of short standard round pipes I9 and 20 have one end of each flanged outwardly, as at 2|. One of each of these pipes is placed at each end of the above assembly and centered therewith, the flange 2| of each pipe being in contact with the outer ends of the strips I3 and the inner ends of the closure plates II of the flues I. The above parts are then secured together with a spot welding machine. In this securing operation, the fingers of the spot welder are passed between the flues I and spot welds made to retain the inner ends of the strips I3 to the peripheries of the coned director plates, and the outer ends of the strips are spot welded to the flanges 2| of the end pipes I9 and 20. One of these latter pipes is then passed through a rotary crimping machine to crimp the extending end, as indicated at 22, so that its diameter will be slightly reduced for entrance into the proper end of one of the sections of a smoke pipe.

When the spot welding and crimping is completed, the finished unit 23 forms a strong construction because all the associated parts are so positioned and connected together that they reinforce each other for rigidity, and cannot be broken apart under ordinary conditions of service. By observing Figure 2 it will be seen that, when the unit is connected in a smoke pipe such as shown at 24 and coming from a heater 25 (Figure l), the gases passing thereup will be definitely dispersed into the flat flues by the lower director plate I5, and as so much surface area is presented by these flues to the surrounding atmosphere, a very large heat transfer will occur between the gases and the outer air, especially as the air can pass right through the centre of the unit. In the same way, the upper director plate I will assist in redirecting the gases back to the centre for movement up the chimney, and without vacuum pockets forming thereabove to reduce the gas flow. Accordingly, it will be obvious that the efilciency of the heater will be materially increased.

The installation shown in Figure '7 suggests how a smoke pipe 26 of a furnace 21 could be fitted with this unit. The unit in this installation will be horizontal and an inverted hopper-shaped casing 28 covers same so that cool air can pass therein from the bottom of the hopper, become heated by the unit, and then pass up a connecting pipe 29 to a suitable outlet (not shown) thereabove.

From the above construction it will be seen that I have invented a strong, sturdy and novel construction from fiat material which can be quickly assembled. The director plates I5 can be made from the cut-off corners of the flue blanks and the strips I3 from remnants of the original flat sheets so the material cost is considerably reduced. All parts can be formed on a folder machine and the fastening is quickly done with a spot welding machine. A large surface is provided for heat dissipation to the atmospheric air, it cannot come apart, and yet one or more flues could easily be removed by breaking a few welds with a screw driver and withdrawing a few strips, if repairs or replacements are required on this part of the unit. If desired, flat metal fins could extend from the sides of the flues for increased area of heat dissipation.

What I claim as my invention is:

1. A heat saving unit, comprising: an annular series of lengthwise flues; each of said flues of a wedge-shape cross section with the pointed edge thereof facing inwardly of said flue series; the pointed end corners of each of said flues cutoff at an angle to form triangular-shaped openings into said flues; strips connecting the ends of said flues together, at said cut-ofi corners, to space said flues apart and provide passageways therebetween and through said unit; and a pair of circular pipes, connected to said flue series, one at each end thereof, and in communication with the triangular-shaped openings at the cutoff ends of said flues.

2. A heat saving unit, comprising: an annular series of spaced lengthwise flues; each of said flues having a relatively pointed edge therealong and facing centrally of said fiue series; each of said flues having the inner corners thereof cutoff at an angle; means closing off the right angled ends of said flues; means connecting and spacing the cut-oif ends of said flues to provide passages therebetween and through said unit; pipe means positioned centrally at each end of said unit and in communication with said flues, through the openings at said cut-01f corners; and direction plates closing off the ends of the central space between said flues.

3. A heat saving unit, comprising: an annular series of lengthwise flues; each of said flues of a wedge-shape in cross section with the pointed edge thereof of each facing inwardly of said fiue series; the pointed end corners of each of said flues cut-off at an angle and with the edges thereof bent outwardly in a folded shelf; strip members slidably receivable on said folded shelves to connect the ends of said flues in spaced relation and form passageways therebetween and through said unit; a pair of pipe members, one at each end of said series of flues, secured to said strip members and in communication with said flues, through the tirangular-shaped openings at said cut-off corners thereof; and director plates receivable in the central space between said flues, closing off the ends thereof, and secured to said strip members.

References Cited in the file of this patent UNITED STATES PATENTS 

